High speed pattern changer



July 6, 1965 H. T. O'NEILL HIGH SPEED PATTERN CHANGER 4 Sheets-Sheet 1 Filed Oct. 15, 1963 INVENTOR. HARRY 7. O'Ni/LL ATTOKAQE'YS H. 'r. O'NEILL v 3,192,957

HIGH SPEED PATTERN CHANGER July. 6, 1965:

Filed Oct. 15, 1963 4 Sheets-Sheet 2 INVENTOR. Is /me) 7: OWE/ BY L puaw e w A7 Takalt/s July 6, 1965 H. 'r. O'NEILL.

HIGH SPEED PATTERN CHANGER Filed Ot. 15, 1963 4 Sheets-Sheet 3 V INVENTOR. HAIFRY 7.' O'NEILL amw/w ATTORA/'YS July 6, 1965 Filed Oct. 15, 1963 H. T. O'NEILL HIGH SPEED PATTERN CHANGER 4 sneaks-sheet 4 93 F IG. 5 90 92 r p9 l/fl m; I 1? 0i //3 97 V 9! m {if [62,0 1; J

INVENTOR. HARE) 7.' O'NEILL @M ZMIM ATTORNEY United States Patent .0

3,192,957 HIGH SPEEB PATTERN CHANGER Harry T. ONeill, New Bedford, Mass., assignor to The Continental Elastic Corporation, New Bedford, Mass. Filed Oct. 15, 1963, Ser. No. 316,294 8 Claims. (Cl. 139-55) This invention relates to the art of weaving and more particularly to a high speed pattern changer for cam operated looms.

As conducive to an understanding of the invention, it is noted that in looms of the type in which a shed is formed by raising and lowering heddle frames carrying a group of warp threads in order thata filler or weft thread may pass through the shed thus formed, Where the heddle frames are raised and lowered through suitable linkage by means of a plurality of cams directly mounted on a common shaft, since the number of actuating regions on the cam is dependent on the size thereof, the complexity of the patterns that can be formed is necessarily limited and.

generally to repeats of not more than eight picks, i.e., the pattern must be repeated every eight picks or less.

Thus, if a more intricate pattern is desired, the size of the cam would have to be increased in order to permit more reciprocation of the heddle frames in each cycle of the loom and such a large cam would be difncult to rotate at high speeds and would require a great deal of power for this purpose.

Furthermore, as the cams are fixed on the same cam shaft, each time another pattern is desired, it would be necessary to stop the loom and change the cam arrangement which would be extremely time consuming.

Where to provide a more complex pattern, a dobby head pattern changer is employed which requires a multiplicity of sensing devices that are controlled by a series of punched openings in a moving pattern card, due to'the time required for each sensing operation and subsequent mechanical response of the lifting mechanism for the heddle frames, the speed of movement of the cards and hence the speed of weaving is necessarily limited, for at high speeds the sensing means may not function properly with the result that picks may be missed in the woven fabric.

Where electric solenoids are used to raise and lower the heddle frames and a punched tape is used to control the operation of the solenoids, such solenoids would have to be relatively large and require large power to move the rather heavy weight of a heddle frame where each frame carries a plurality of sets of heddle wires and a plurality of strips of fabric or tape are woven at one time.

In addition, the tension of a large number of warp threads also adds to the power requirements, as does the mass of the solenoids themselves. As a result, large solenoids and relatively great power is required and due to the inherent hysteresis of the large solenoids the operation would be relatively slow.

It is accordingly among the objects of this invention to provide a cam operated loom that can operate at high speeds and will provide an extensive predetermined variable pattern, whose repeat length is in excess of 32 complete sheddings of the loom and which patterns may be varied Without any physical change in the configuration of the cams, but merely require actuation of the cams at predetermined portions of the loom cycles and the reliability of operation of which to provide a uniformly woven fabric without missing picks is not effected by the mass or weight to be actuated by the cams.

According to the invention, these objects are accomplished by the arrangement and combination of elements hereinafter described and more particularly recited in the claims.

In the accompanying drawings in which are shown one 3,192,957 Patented July 6, 1965 of various possible embodiments of the several features of the invention:

FIG. 1 is a top plan view with parts broken away of a loom in which the invention is incorporated,

FIG. 2 is a view similar to FIG. 1 showing the heddle frame actuating means,

FIG. 3 is a view taken along line 3-3 of FIG. 2,

FIG. 4 is a view taken along line 44 of FIG. 2,

FIG. 5 is a longitudinal sectional view of the cam drive assembly,

FIG. 6 is a plan view of an actuating cam, and

FIG. 7 is a diagrammatic view of the tape sensing circuit.

Referring now to the drawings, the invention which is the subject matter hereof is illustratively incorporated into a shuttleless loom of the type shown in Patents Nos. 2,180,831 and 2,980,146.

Thus, for example, referring to FIGS. 1 to 3, the loom comprises takeup rollers 11 which draw the finished web 12 that is formed from warp threads 13 fed from suitable supply rolls (not shown) through the eyes 14 of heddle wires 15 carried bysheddle frames 16 to forma shed 17.

Positioned laterally of the web 12 is a disc 18 mounted on a vertical shaft 19 and driven in suitable manner so as to rotate in a clockwise direction. Rising from disc 18 adjacent its periphery and rotatably mounted thereon is a rod 21 which carries a block 22 at its upper end that has.

a transverse bore therethrough.

Positioned in said bore and secured therein as by set screw 23 is one end of a weft filling needle 24' which is. slidably positioned in the transverse bore of a block 25 rotatably mounted on a base 26 on the same side of the web 12 as the shaft 19.

Cooperating with the filling needle 24 is a knitting needle 27 which extends parallel to the web onthe side thereof remote from disc 18. The needle 27, which is carried in a reciprocable carriage block 28, is of conventional type having a hook 31 at one end and a pivotedlatch bar 32 adjacent said hook end.

A reed 35 is provided for beating up the filling toward the fell of the shed in conventional manner.

The equipment thus far described is not per se new being substantially shown and described in said Patents Nos. 2,180,831 and 2,980,146.

The equipment above described will weave the fabric in conventional manner as more fully set forth in said patents. However, it is to be noted that the pattern woven is determined by the position of the warp threads 13 which are raised or lowered by the heddle frames 16 to form a shed and the filling needle 24 follows the path shown by.

plurality of sets 50 of heddle wires 15, the respective warp threads 13 extending through an associated eye 14 in conventional manner.

Means are provided to reciprocate the heddle frames. To this end, as shown in FIG. 4, a support block 57 is mounted on and rises from a beam 58 extending transversely between the side walls 52, 53 of the loom frame j beneath the heddle frames, the block 57 being illustratively positioned adjacent the side wall 52 of the loom frame.

Rotatably mounted on a shaft 59 carried by block 57 are a plurality of parallel bell-crank levers 61 corresponding in number to the number of heddle frames. The free end of one of the legs 62 of each lever is pivotally connected as at 63 to one end of a lifting rod 64, the other end of which is pivotally connected as at 65 to the lower edge of an associated heddle frame 16.

The free end of the other leg 66 of each lever 61 is pivotally connected as at 67 to one end of a pitman 68, the other end of which is pivotally connected as at 69 to one end of the cross piece 71 of a T-shaped cam follower arm 72, the free end of the central leg 73 of which is pivotally connected as at 74 to the beam 58.

The other end of cross piece 71 is pivotally connecte as at 75 to one end of a tie rod 76, the other end of which is pivotally connected as at 77 to the end of one of the legs 78 of a bell-crank lever 79, pivoted as at 81 to a bracket 82 extending laterally inward from the wall 53 of the frame. The free end of the other leg 83 of lever 79 is pivotally connected as at 84 to one end of a lifting rod 85, the other end of which is pivotally connected as at 86 to the lower edge of heddle frame 16 on the other end thereof.

With the arrangement above described, it is apparent that when the cam follower arms 72 are rocked in a clockwise direction from their extreme position to the left as shown in FIG. 4, to their extreme position to the right and vice versa, the heddle frameswill be raised and lowered.

Associated with each of the cam follower arms 72 is a drive assembly 90 which, as shown in FIG. 5, comprises a cam 92 which has a cam groove 93 in one face thereof in which rides a roller 94 rotatably mounted on the central leg 73 of the cam follower 72 between the ends thereof.

The cam 92 is keyed as at 95 to a shaft 96 rotatably mounted in standards 97, 98 secured to beam 58, a conventional electro-magnetic clutch and brake unit 99 being secured to each shaft 96.

As shown in FIG. 5, the unit 99 which may be of the type put out by The Warner Electric Brake and Clutch (30., under the name Electro-Pack Model EPSr, comprises a braking portion 101 having an electro-magnet 102 through which shaft 96 extends, the end of shaft 96 having an armature 103 keyed theretoas at 104. The magnet 102 is secured by screws 105 to standard 98 and a braking face plate 106 is secured by slidably mounted pins 107 to the side of the armature 103 adjacentsaid magnet 102.

Associated with the armature 103 and on the other side thereof is an electro-magnet 108 which forms part of a clutching section 109. The magnet 108 is secured by screws 110 to a collector ring member '111 keyed as at 112 todriving shaft 113 mounted on standard 114, the collector rings 115 of member 111 being electrically connected to magnet 108 and engaging contacts 116 mounted on a terminal block 117 carried by standard 114.

A clutching face plate 118. is secured by slidably mounted pins 119 to the side of the armature 103 adjacent collector ring member 111. 7 Y

Atfixed to the outer end of each of the shafts 113 is a bevel gear 121 which. is engaged by a corresponding bevel gear 122 secured to common shaft 123 that has a bevel gear 124 at its end (FIG. 4).

Bevel gear 121 is engaged by a bevel gear 125 secured to a shaft 126 that is driven through engaging bevel gears 127, 128 by main drive shaft 128, the latter being connected through gear box 130 to the main drive motor 132.

Shaft 129 also mounts gears 131 which through conventional transmission drives the takeup rollers 11, the shaft 19, carriage block 28 as Well as the other moving elements of the loom.

As shown in FIG. 6, each of the cams 92 is of theitwo position type having a high portion 135 and a low portion 136, each illustratively occupying an arc of 30 degrees. Thus, when the cam follower roller 94 is engaged by either the high or low portions 135, 136 of the groove 93, there will be no pivotal movement imparted to the associated arm 72 and only when the follower roller 94 is adjacent such portions 135, 136 will movement be imparted.

As illustratively shown, in FIG. 4, when the follower roller 94 is engaging the high portion135 of the cam, the associated heddle frame 16 will be in its lowermost position.

In order to control the reciprocation of the heddle frames 16 and hence the pattern to be woven, a pattern control tape 141 is provided. As shown in FIG. 4, the tape rides around sprockets 142, 143, the sprocket 142 being mounted on shaft 123 so as to be driven in timed relation therewith.

The tape is punched with parallel pairs of rows 144, 143 of elongated slots or perforations 146, 147, two rows being required for each of the cams 92. The slots 146 in row controls clutch magnet 108 and the slots 147 in row controls the brake magnet 102 as more fully hereinafter described.

More particularly, referring to FIG. 7, a micro-switch MS-i, MS-2 is positioned over the rows 144, 145 respectively and each has a contact arm 148 designed to enter the associated slots 146, 147 to actuate the micro-switch as the tape is advanced.

As shown in FIG. 7, the micro-switch MS1 is normally open and micro-switch MS-2 is normally closed. One of the terminals of micro-switch MS1 is connected to a source of current and the other terminal is connected to one end of coil 151 of relay 152 and also to the contact arm 153 of said relay 152 which is spaced from fixed contact 154, the latter being connected to said source of current. The other end of coil 151 is connected to one of the terminals of normally closed micro-switch MS-Z and the other terminal of said micro-switch MS-Z is connected to ground return for the current.

The relay 152 has two additional pairs of contacts 155, 156 and 157, 158, the former being open when the coil 152 of the relay is not energized and the latter being closed.

Contacts 156, 157 are connected to the source of current. Contact is connected to terminal 161 (FIG. 7) which in turn is connected to terminal 162 (FIG.'5) which is connected through the associated collector rings 115, 116 to the clutch magnet 108 and then to ground return.

Contact 158 is connected to terminal 163 which is connected to terminal 164 (FIG. 5) that is connected to one side of brake magnet 102, the other side of the brake magnet being connected to ground return.

As the operation of the loom insofar as the actual weaving is concerned is conventional and has been fully described in said Patents Nos. 2,180,831 and 2,980,846, it will not be repeated.

The present invention is concerned with the actuation of the harness frames and this operation will be fully described.

In setting up the equipment for operation, the warp threads 13 are threaded through the heddle eyes 14 in conventional manner and the heddle frames 16 are all set in their lowermost position with the follower rollers 94 positioned in the associated groove 93 aligned with the beginning or" the high portion 135 or at the beginning of the 30 degree arc indicated as 0 degree in FIG. 6.

The tape 141 is adjusted so that the leading edge 171 of the first slot 146 in any one of the rows 144 is aligned with the leaf 148 of the associated micro-switch MS-l and consequently such leading edge will be synchronized with the Zero degree position of the cams.

It is to be noted that the leading edge 171 of the slots 146, 147 in the rows 144 and 145 are spaced in increments of degrees with respect to the cam 92 so that if the associated micro-switch MS1, MS-Z is energized, it will be energized at the beginning of each of the 30 degree arcs.

When power is turned on and the main drive motor 132 is energized, the shaft 129 will begin to rotate and the filling needle 24 will start to move in the path shown by the broken lines in FIG. 1. Thus, substantial rotation of shaft 129 will occur before the filling needle 24 starts to enter the shed 17 (FIG. 3).

As soon as power is turned on, as the tape 141 is now advanced to the left (FIG. 2) by reason of the drive imparted to sprocket wheel 142 which begins as soon as shaft 129 begins to rotate, since the leaf 148 of mirco-switch MS-l associated with row 144 is aligned with the leading edge 171 of slot 146, the leaf will move downwardly, closing the circuit to coil 151 of relay 152. Referring to FIG. 7, energization of coil 151 will close contacts 155, 156; 153, 154 and open contacts 157, 158. When contacts 155, 156 close, the clutch magnet 108 will be energized and when contacts 157, 158 open, the brake magnet 102 will be deenergized. Energization of clutch magnet 108 will cause the clutch plate 118 to engage magnet 108 to provide a positive drive between armature 103 keyed to cam shaft 96 and collector ring member 111 keyed to drive shaft 113.

Since the cam follower roller 94 at this time is in the arcuate portion 135 of the cam groove 93, there will be substantially no load imparted to the clutch plate by the associated heddle frame 16 and slippage between the clutch plate 118 and the clutch magnet 108 is minimized. Hence, positive engagement will occur extremely rapidly, in the order of a few degrees rotation of the main drive shaft 129 and thereupon the cam 92 will start to rotate and through the cam follower arm 72 the heddle frame 16 will be lifted. It is to be noted that no motion is imparted to the heddle frame 16 until the cam 92 has rotated 30 degrees in a counterclockwise direction from the position shown in FIGS. 4 and 6 and upon 150 degrees further rotation of the cam, the heddle frame will have reached its uppermost position where it will remain even with additional rotation of the cam, due to the 30 degree arcuate portion 136.

Assuming that it is desired to retain the heddle frame 16 in its uppermost position for two loom cycles, i.e. two complete reciprocations of the needle 24 through the shed 17, which illustratively requires 720 degrees rotation of main drive shaft 129, then the pattern tape is provided with a slot 147 in row 145, the leading edge 171 of which is longitudinally displaced from the leading edge 171 of slot 145 by a distance corresponding to 360 degrees of rotation of needle shaft 19.

Thus, when the cam 92 has been rotated 180 degrees at which time the needle shaft 19 will have rotated 360 degrees, the micro-switch MS2 will be actuated to open its contacts thereby breaking the holding circuit of coil 151 through closed contacts 153, 154.

As -a result or" the deenergization of relay 152 its contacts 157, 153 will close to energize brake magnet 102 and its contacts 155, 156 will open to deenergize clutch magnet 108,

As a result of the energization of brake magnet 192, the cam shaft 96 will be securely locked in fixed position with respect to standard 8 to which the brake magnet is secured, thereby retaining the cam 92 in fixed position, to retain the heddle frame 16 in its uppermost position.

It is apparent that since each cam 92 has an associated pair of rows of slots 144, 145 on tape 141 and each pair of rows has the associated-circuit shown in FIG. 7, by merely preparing the tape with slots in the desired position, the movement of the heddle frames 16 may be controlled to provide the desired pattern.

To summarize the operation, it is apparent that starting from zero position of cam 92, and with the end of the filling needle 24 fully retracted and at the point X on the broken lines, shown in FIG. 1, and with the leading edge 171 of slot 146 in strip 141 aligned with the leaf 148 of micro-switch MS-l, as the speed of rotation of the needle shaft 19 illustratively is twice that of cam shaft 96, when the equipment starts to operate, the following sequence will occur:

(a) Clutch magnet 108 will be energized to connect' 5 drive shaft 113 to come shaft 96 and cam 92 will start to rotate in a counterclockwise direction from zero position and brake magnet 1&2 will be deenergized.

(b) Due to the 30 degree arcuate portion 135 ofcam 92, no motion will be imparted to the heddle frame 16 until after the cam has rotated 30 degrees.

(c) The leading end of needle 24 will follow the broken line path in FIG. 1 and only after the heddle frame 15 has been lifted to form the shed will the needle 24 enter the shed.

(d) The speed of rotation of shaft 19 compared to the speed of rotation of cam shaft 95 is such that the needle will enter and retract from the shed during one shed formation.

(e) When the leading edge of slot 147 in row 145 is aligned with the leaf 148 of micro-switch MS2, the latter will be energized during the period that the roller 94 is in the low portion 136 of cam 92 and as a result the circuit to the coil of relay 152 will be broken.

(f) Deenergization of relay 152 will cause brake magnet 192 to be energized and clutch magnet 168 to be deenergized thereby retaining the heddle frame in its uppermost position with cam roller 94 retained in the arcuate portion 136.

(g) As a result, in the next 360 degree rotation of shaft 19, the needle will again move into and out of the shed and when the leading edge 171 of the second slot 146 in row 144 is aligned with leaf 148 of micro-switch MS1 the relay 152 will again be energized to cause the brake magnet 101 to be deene'rgized and the clutch magnet 198 to be energized. This will cause the cam 92 to rotate again until roller 94 is at the zero position, i.e., the beginning of the arcuate portion 135 and the heddle frame 15 to be moved to its lowermost position.

The cycle thus described will be repeated at intervals based on the sequence of slots in rows 144, 145 which determine the pattern.

With the construction above described, it is apparent that force will only be applied to the heddle frames 16 by the cams 92 during the portion of the cycle when the cam follower rollers 54 are outside the arcuate portions 135, 136.

As a result, since the clutch is energized only during the arcuate portions, there will be no load applied to the clutch which therefore can lock almost instantaneously so that no slippage occurs and hence the timing of the shed formation and the filling needle movement remain in synchronization.

As no load is directly transmitted to the clutch when it is locking, the clutch magnet need only be relatively small in size and requires little power for energization. Once the clutch is fully closed, little power is required to maintain it in such condition and only then is the cam in the position to apply force to the heddle frames.

Since the cam need only have a high and low portion yet with the arrangement above described can still produce a great number of patterns, it can be driven at relatively high speeds with relatively little power so as to provide a highly efiicient operation.

By reason of the fact that the transmission of force from the cams to the heddle frames once the clutches are energized, is a direct transmission, the loom is capable of high speed operation without missing of picks which can occur with the (lobby head changer.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope of the claims, it is intended that all matter contained in the above description or shown in the accompanying drawings'shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. In a loom having means for forming a shed from longitudinally extending warp threads, and means to move a filling thread substantially transversely through the shed to weave a fabric, said shed forming means comprising a plurality of spaced parallel heddle frames extending transversely across the warp threads, each of said frames carrying a plurality of heddle wires each having an eye to accommodate a Warp thread, means mounting said heddle frames for vertical reciprocation; the combination therewith of a plurality of cam shafts corresponding in number to the number of heddle frames, a cam carried by each cam shaft, drive means for said cam shafts, said drive means being normally disconnected from said cam shafts, means selectively to connect said drive means to said cam shafts for a predeterminedinterval, linkage between each of said cams and an asscciatedheddle frame to reciprocate the latter to form the shed with rotation of said cams, each of said cams having arcuate portions during which no driving motion will be imparted to the associated linka e, whereby said cams will impart driving motion to the associated linkage only after said drive means has been connected to said cam shaft and said cam has rotated at predetermined amount.

2. The combination set forth in claim 1 in which each of said cams has two opposed arcuate portions during which no driving motion will be imparted to the associated linkage.

3. The combination set forth in claim it in which each of said linkages includes a cam folio. er operatively engaged by an associated cam and each of said cams has a cam follower engaging surface which includes two opposed arcuate portions, whereby when said cam is rotated and said cam follower is aligned with said arcuate portions, no driving motion will be imparted to said linkage.

4. The combination set forth in claim 1 in which the means selectively to. connect said drive means to an associated cam comprises an electric clutch having two clutch elements including an electro-magnet and a clutch plate, said clutch elements eing connected respectively to said drive means and said cam shaft, and control means to energize said clutch at predetermined intervals and when said cam follower is aligned with one of said arcuate portions of said cam.

5. The combination set forth in claim 4 in which an electric brake is associated with said cam shaft and means are provided to energize said brake when said clutch is deenergized to retain said cam shaft in its set position.

6. The combination set forth in claim 4 in which an electric brake is associated with said cam shaft, said brake having two braking elements including an electromagnet and a brake plate, a fixed mount, said braking elements being connected respectively to said fixed mount and said cam shaft, and means are provided to energize said brake when said clutch is deenergized to retain said cam shaft in its set position.

7. In a loom having means for forming a shed from longitudinally extending warp threads, and means to move a filling thread substantially transversely through the shed to weave a fabric, said shed forming means comprising a plurality of spaced parallel heddle frames extending transversely across the warp threads, each of said frames carrying a plurality of heddle wires each having an eye to accommodate a warp thread, means mounting said heddle frames for vertical reciprocation; the combination therewith of. a plurality of cam shafts corresponding in number to the number of heddle frames, a cam carried by each cam shaft, drive means for said cam shafts, said means being normally disconnected from said cam shafts, means selectively to connect said drive means to said cam shafts for a predetermined interval, an electric clutch having two clutch elements including an electromagnet and a clutch plate, said clutch elements being connected respectively to said drive means and said cam shaft, an electric brake associated with said cam shaft, said brake having two braking elements including an electro-magnet and a brake plate, a fixed mount, said raking elements bein connected respectively to said fixed mount and said cam shaft, control means to energize said clutch at predetermined inteivals, and when said cam follower is aligned with one of said arcuate portions of said cam and simultaneously to de-energize said brake to retain said cam shaft in set position, said control means comprising an elongated tape having two rows of longitudinally aligned transversely staggered perforations extending the length thereof and sensing means associated with each of said rows and controlling the operation of said clutch and brake, linkage between each of said cams and an associated heddle frame to reciprocate the latter to form the shed with rotation of said cams, each of said cams having arcuate portions during which no driving motion will be imparted to the associated linkage, whereby said cams will impart driving motion to the associated linkage only after said drive means has been connected to said cam shaft and said cam has rotated at predetermined amount. 3

8. The combination set forth in claim '7 in which each of said sensing means comprises a micro-switch having a control leaf actuated by the associated perforation, a relay having a coil in series with said two micro-switches, one of said micro-switches being normally open and the other closed, said relay having a pair of normally open contacts in series with said clutch magnet, a pair of normally closed contacts inseries with said brake magnet and a third pair of contacts adapted to provide a holding circuit for said relay coil whereby when the normally open micro-switch is actuated to energize said relay, said clutch magnet will be energized and said brake magnet will be deenergized, and when said normally closed micro-switch is actuated, said relay and said clutch will be deenergized and said brake will be energized.

References Cited by the Examiner UNITED STATES PATENTS 425,844 4/90 Wright l3977 1,728,438 9/29 Nakanishi 139-319 2,753,894 7/56 Lovshin et a1 139336 2,981,295 4/61 Paul et al 139-336 FOREEGN PATENTS 277,250 11/51 Switzerland.

DONALD W. PARKER, Primary Examiner. 

1. IN A LOOM HAVING MEANS FOR FORMING A SHED FROM LONGITUDINAL EXTENDING WARP THREADS, AND MEANS TO MOVE A FILLING THREAD SUBSTANTIALLY TRANSVERSELY THROUGH THE SHED TO WEAVE A FABRIC, SAID SHED FORMING MEANS COMPRISING A PLURALITY OF SPACED PARALLEL HEDDLE FRAMES EXTENDING TRANSVERSELY ACROSS THE WARP THREADS, EACH OF SAID FRAMES CARRYING A PLURALITY OF HEDDLE WIRES EACH HAVING AN EYE TO ACCOMMODATE A WARP THREAD, MEANS MOUNTING SAID HEDDLE FRAMES FOR VERTICAL RECIPROCATION; THE COMBINATION THEREWITH OF A PLURALITY OF CAM SHAFTS CORRESPONDING IN NUMBER TO THE NUMBER OF HEDDLE FRAMES, A CAM CARRIED BY EACH CAM SHAFT, DRIVE MEANS FOR SAID CAM SHAFTS, SAID DRIVE MEANS BEING NORMALLY DISCONNECTED FROM SAID CAM SHAFTS, MEANS SELECTIVELY TO CONNECT SAID DRIVE MEANS TO SAID CAM SHAFTS FOR A PREDETERMINED INTERVAL, LINKAGE BETWEEN EACH OF SAID CAMS AND AN ASSOCIATED HEDDLE FRAME TO RECIPROCATE THE LATTER TO FORM THE SHED WITH ROTATION OF SAID CAMS, EACH OF SAID CAMS HAVING ARCUATE PORTIONS DURING WHICH NO DRIVING MOTION WILL BE IMPARTED TO THE ASSOCIATED LINKAGE, WHEREBY SAID CAMS WILL IMPART DRIVING MOTION TO THE ASSOCIATED LINKAGE ONLY AFTER SAID DRIVE MEANS HAS BEEN CONNECTED TO SAID CAM SHAFT AND SAID CAM HAS ROTATED A PREDETERMINED AMOUNT. 